Hans de Bruin <jmdebruin@xxxxxxxxx> writes:
>> I expect what needs to happen is to confirm that nfs directory entry
>> revalidation is buggy, and at least for the short term re-add the nfs
>> logic that will avoid dropping a dentry if it is a mount point, or
>> path to a mount point, to avoid the nfs bugs.
>>
>
> ok, I will go in waiting mode.
I dropped the ball on this but it looks like someone else hit the
problem and the following two commits fixed this issue:
Can you confirm that things are working again?
commit fa9233699cc1dc236f4cf42245d13e40966938c5
Author: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Date: Mon Feb 23 18:51:32 2015 -0500
NFS: Don't require a filehandle to refresh the inode in nfs_prime_dcache()
If the server does not return a valid set of attributes that we can
use to either create a file or refresh the inode, then there is no
value in calling nfs_prime_dcache().
However if we're just refreshing the inode using the attributes that
the server returned, then it shouldn't matter whether or not we have
a filehandle, as long as we check the fsid+fileid combination.
Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
commit 6c441c254eea2354d686be7f5544bcd79fb6a61f
Author: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Date: Sun Feb 22 16:35:36 2015 -0500
NFS: Don't invalidate a submounted dentry in nfs_prime_dcache()
If we're traversing a directory which contains a submounted filesystem,
or one that has a referral, the NFS server that is processing the READDIR
request will often return information for the underlying (mounted-on)
directory. It may, or may not, also return filehandle information.
If this happens, and the lookup in nfs_prime_dcache() returns the
dentry for the submounted directory, the filehandle comparison will
fail, and we call d_invalidate(). Post-commit 8ed936b5671bf
("vfs: Lazily remove mounts on unlinked files and directories."), this
means the entire subtree is unmounted.
The following minimal patch addresses this problem by punting on
the invalidation if there is a submount.
Kudos to Neil Brown <neilb@xxxxxxx> for having tracked down this
issue (see link).
Reported-by: Nix <nix@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/87iofju9ht.fsf@xxxxxxxxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx # 3.18+
Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
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